Description of problem:
We are using a real FTP proxy not http to ftp proxy, and that's not supported by python urlgrabber and python urllib2 and therefore yum.

Version-Release number of selected component (if applicable):
python-urlgrabber-3.1.0-6.el5

How reproducible:
setup a ftp proxy in your environment and use for example spacewalk-repo-sync (every sync command will failed)

Steps to Reproduce:
1.export ftp_proxy=ftp://myproxy:21
2.spacewalk-repo-sync --url=ftp://whatever/some/where my_channel

  
Actual results:

Traceback (most recent call last):
  File "/usr/bin/spacewalk-repo-sync", line 72, in ?
    sys.exit(abs(main() or 0))
  File "/usr/bin/spacewalk-repo-sync", line 66, in main
    sync.main()
  File "/usr/share/rhn/satellite_tools/reposync.py", line 103, in main
    self.import_packages(plugin, url)
  File "/usr/share/rhn/satellite_tools/reposync.py", line 135, in import_packages
    packages = plug.list_packages()
  File "/usr/share/rhn/satellite_tools/repo_plugins/yum_src.py", line 57, in list_packages
    sack.populate(repo, 'metadata', None, 0)
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 168, in populate
    if self._check_db_version(repo, mydbtype):
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 226, in _check_db_version
    return repo._check_db_version(mdtype)
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1233, in _check_db_version
    repoXML = self.repoXML
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1406, in <lambda>
    repoXML = property(fget=lambda self: self._getRepoXML(),
  File "/usr/lib/python2.4/site-packages/yum/yumRepo.py", line 1402, in _getRepoXML
    raise Errors.RepoError, msg
yum.Errors.RepoError: Cannot retrieve repository metadata (repomd.xml) for repository: test-epel-i386-server-5. Please verify its path and try again

Expected results:
correct synchro or a clean error message

Additional info:

A ftp proxy is working that way in command line :
$ ftp my.proxy
ftp-prompt> anonymous.ftp
Password: ******
ftp-prompt>

I manage to hack urllib2.py and byterange.py to make it work, but that's really too dirty, I'll like to a have a real fix.

Thanks,
  Thomas